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How to Calculate Dosing Requirements

05/23/2012 9:06 AM

Hello guys,

I have a 1000 liters tank that we want to use with our filling machine. I wanted to add 10 percent concentrate with 1000 liters of water. How can i select the proper dosing pump for this purposed? thanks

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#1

Re: How to calculate dosing requirements

05/23/2012 9:13 AM

10% of 1000litres is 100 litres.
How fast do you need to dose it into the machine and how often?
What is the composition of the concentrate? Are there chemical compatibility issues?
Answer these Qs and you'll have some sort of idea where to start looking.
Sounds a bit too much for a peristaltic which is my thing. maybe a big piston pump or diaphragm pump?
Del

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#3
In reply to #1

Re: How to calculate dosing requirements

05/23/2012 9:22 AM

hi, thanks for your reply, the concentrate is a sort of flavour that I want to mix with our drinking water. our filling tank has a capacity of 1000 liters. the water is supplied from water treatment plant. what i wanted to know is how can i set the dosing pump to get the required percentage of concentrate into the filling tank. thanks

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#4
In reply to #3

Re: How to calculate dosing requirements

05/23/2012 9:59 AM

Try using an ejector. The water goes in the main route and the concentrate goes in the side port.

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#6
In reply to #4

Re: How to calculate dosing requirements

05/23/2012 10:06 AM

You have to control the concentrate infusions.

We use eductors (ejectors) for producing brine, with simular concentrations but that is not as critical.

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#5
In reply to #3

Re: How to calculate dosing requirements

05/23/2012 10:05 AM

You need to dose in proportion to the amount of water entering (or leaving) the tank.
So a diaphragm pump driven from a water meter will do the job.
You still need to know how much water is being consumed on a daily/hourly basis. The tank will need an initial dose of 100L put in manually to account for the water in there.
or you could just leave it alone and mix the flavour at the point of use.
Del

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#7
In reply to #5

Re: How to calculate dosing requirements

05/23/2012 10:22 AM

thanks Del, actually I want to install the dosing pump at the inlet of the water tank. there is solenoid valve at the inlet and the tank has a water level sensor. what i was trying to do is when the level of the water goes down, the solenoid valve will open to feed the water and at the same time dosing pump will start to dose. but i want to know the calculation of setting the dosing pump either g/h or l/h to have a required percentage of dosing.

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#9
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Re: How to calculate dosing requirements

05/23/2012 10:30 AM

What about the mixing?

1000L is a lot of liquid to sort out of the concentration is wrong.

What about biological activity? Is this tank covered? Does it have a clean-in-place system fitted? Cleaning agent drain connections and flushing? Can the effluent treatment plant cope?

Is it still a tank or is it an ejector yet?

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#11
In reply to #9

Re: How to calculate dosing requirements

05/23/2012 10:50 AM

thanks bro...i only need to know the proper setting of the dosing pump here. other things like CIP system can be deal separately and at a later time.

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#12
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Re: How to calculate dosing requirements

05/23/2012 11:37 AM

Why dosing?

How about 900 liters af water, 90 liters of flavor agent, and agitate/mix?

Think horses, not zebras. Or maybe, the K.I.S.S principle.

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#14
In reply to #12

Re: How to calculate dosing requirements

05/23/2012 12:04 PM

yes but i need it in a continues process that is why I intend to use dosing pump. we have a filler that fill 7000 cups per minutes.

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#15
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Re: How to calculate dosing requirements

05/23/2012 12:12 PM

Then a tank is not needed, because a tank turns the process into semi-batch with biological risks, whereas an eductor and static mixer is useful for continuous operation with periodic clean-in-place. After all, the filling machine is cleaned somehow, and the same process and procedure will clean the ejector and static mixer with minimal impact.

Unless the concentrate is going in the tank? The only purpose of a tank is to let the level go up and down. Why this fixation on the tank?

How do other facilities do it within the group? How do competitors do it?

Where is the Process Engineer in all this?

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#16
In reply to #14

Re: How to calculate dosing requirements

05/23/2012 1:03 PM

If your 7,000 cups = 1,750 LPM, you need a dosing pump that can deliver 175LPM.

A tank is good to assure a constant supply to the filling machine.

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#13
In reply to #9

Re: How to calculate dosing requirements

05/23/2012 11:39 AM

CIP, the type of valves would be block and bleed with leak protect. good adder

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#17
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Re: How to calculate dosing requirements

05/23/2012 1:16 PM

Ah, what you are doing there is what I call a tank top up system.
If you calculate the volume of water in the tank from the level switch activating (and the solenoid coming on) to the solenoid going off (controlled by another switch of by a timer?) Thats just some basic arithmetic, once you know that volume, you calculate 10% of that and then get a pump with built (or external) timer, and set it to run for long enough to dose the required amount based on the pump manufacturers figures or a measured timed dose (run it for a minute and measure the delivery).

Eductors are okish if the water is soft and free from crud, but they can leak and spew water everywhere, thay can also wear or get furred up. But then pumps can need servicing.

BTW, I've since read the application and I agree with some of the other's comments
Del

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#33
In reply to #7

Re: How to calculate dosing requirements

05/24/2012 4:08 PM

Pretty simple: If the water entering the tank is 1000 L/h, then the dosing pump has to deliver 100 L/h to meet the volumetric 10% value, if 10% by weight, then factor in the specific gravity (divide by). For such a rate, the dosing pump need be fairly high capacity, probably up to 150 L/h range, and cut it back either by pulsation rate, or by stroke length as a percentage of the maximum dosing rate.

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#8
In reply to #3

Re: How to calculate dosing requirements

05/23/2012 10:25 AM

This sounds like you are bottling a soft drink. Is this a description of your project?

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#10
In reply to #8

Re: How to calculate dosing requirements

05/23/2012 10:32 AM

we are manufacturing of bottled drinking water and we are planning for a flavor drinking water.

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#2

Re: How to calculate dosing requirements

05/23/2012 9:13 AM

Give this information to the dosing pump suppliers and let them tell you what you need.

This isn't rocket science.

Find pump suppliers here: Search GlobalSpec

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#18

Re: How to Calculate Dosing Requirements

05/23/2012 5:56 PM

I'd look at it from a slightly different angle.

Two electromagnetic flowmeters (one for water one for concentrate), a PLC and variable speed drive on the flavour dosing pump, controlled by the flow rate input from the water line.

Calibration is then possible and repeatable outcomes.

As previously stated though, you need to have the initial batch manually set, or else start with an empty tank.

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#19
In reply to #18

Re: How to Calculate Dosing Requirements

05/23/2012 7:15 PM

I think all you need is a timer that controls both pumps. Dump into the tank for x minutes, then off for x minutes to let the level drop. Or, just do a continuous feed into the dispenser. It's easy enough to set the ratios.

Your way is more precise and with the pumps controlled by flow they will both stop if one fails.

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#20

Re: How to Calculate Dosing Requirements

05/24/2012 12:28 AM

I seriously think some info is missing here in the OP's first posting....and I think everyone is missing it as well, or am I way off base here (see my comments below)? Pardon me for being too tired as it's been a long long day.

OP: Let me get this straight, okay? You're adding a 10% strength concentrate of some syrup (or whatever) into 1,000 gallons of potable water, correct?

BUT, what is the intended (desired) strength of the mixture, say if it is a batch process, in mg/L? Forget about flow through dosing for the moment. See what I mean? Without knowing what the intended concentration (say in ppm = mg/L) first you can't figure out what the dosing pump injection rate has to be set at.

Now, with a injection port on a process line you need to know the flow rate through it and what the dosing concentration is (introduced for the batch reactor after complete mixing) in order to calculate the injection flow rate needed from the dosing pump, and hence the settings.

It's just like the chlorination process found in small water treatments plants: adding 12.5% Sodium Hypochlorite into a batch vessel of known volume to make "W" mg/L concentration, then withdrawing the mix and pumping it out with a dosing pump delivering @ "X" feed rate (@ mL/Hr. or mL/min.), and finally injecting it into the raw filtrate process line flowing @ "Y" L/min. or gallons/min. before it gets to the clearwell.

See what I mean?

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#24
In reply to #20

Re: How to Calculate Dosing Requirements

05/24/2012 3:46 AM

Yes. Absolutely.

The posting is starting with the tank and making it fit. The design needs to start from the process and select the equipment that will best do the job.

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#21

Re: How to Calculate Dosing Requirements

05/24/2012 12:29 AM

1,000 liters = 1,000 kg of water. When you say 10% concentrate, do you mean that the concentration of your dosing solution is 10% or do you mean that you want a 10% concentrate solution in your tank after dosing? If it's the former, what is your final required concentration? If it's the latter, then you need to add in 100 kg of concentrate.

What is your volumetric flow rate to fill up the tank? For example, if by 10% solution you mean 10% of concentrate in your water, then a volumetric flow rate of 100 liters/minute of water will require you to dose in 10 kg of concentrate per minute into the water assuming that the concentrate is in liquid form. To find the volumetric flow rate for the pump, divide the mass flow rate by the density of the concentrate.

I hope that this helps.

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#22
In reply to #21

Re: How to Calculate Dosing Requirements

05/24/2012 12:51 AM

Hey D, I beat you to the same question by a whole minute buddy! My 12:28 AM to your 12:29 AM.....LOL

It looks like we're on the same page!!!!

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#25
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Re: How to Calculate Dosing Requirements

05/24/2012 5:27 AM

Yup.

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#23

Re: How to Calculate Dosing Requirements

05/24/2012 1:01 AM

We use a "dosatron" unit that works very well even with harsh materials. You plumb it inline with your water supply and it automatically injects a percentage or ratio of your concentrate into the stream going to your tank. You can buy them in various ratio "ranges". Accurate and bulletproof. www.dosatronusa.com.

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#26
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Re: How to Calculate Dosing Requirements

05/24/2012 5:32 AM

So the tank has been put to better use there, then?

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#27

Re: How to Calculate Dosing Requirements

05/24/2012 10:03 AM

Another possible approach is thru the use of fluid conductivity measurements in determining your proper liquid mixture. The concentrate pump will either speed up or slow down depending on a preset fluid conductivity reference as compared to the final fluid conductivity as measured on the output side. The peristaltic type concentrate pump will be using a concentrate tubing with known displacement volume per unit revolution.

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#28
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Re: How to Calculate Dosing Requirements

05/24/2012 10:28 AM

Conductivity, oxidation reductional potential, Ph can all be used, depending on the chemistry of the solutions. These all require more expensive and more failure prone sensors to be effective.

KISS.

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#29
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Re: How to Calculate Dosing Requirements

05/24/2012 1:09 PM

True, yet its for more accurate applications.

Expensive ? Yes, only need some electronic logic ckt. to control pump

prone to sensor failure ? No, only 2 non-corrosive steel probes along the fluid path - nothing to break.

controlled accuracy? Yes

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#30
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Re: How to Calculate Dosing Requirements

05/24/2012 1:16 PM

As a consumer I would worry more about pathogens (as has been mentioned) than the mix be exactly 10% by volume.

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#31
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Re: How to Calculate Dosing Requirements

05/24/2012 1:23 PM

problem is, what is the mix, also determined the risk

protiens? (doubtful)

sugars? more than likely

minerals? who knows

I think its time for me to take a hiatus from CR4.... again

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#32
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Re: How to Calculate Dosing Requirements

05/24/2012 2:04 PM

I believe the aseptic integrity of any system is and will be dependent on how they're designed, applied or used. Continued system sterility will rely on how they are maintained as well as its environment protected.

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